SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '191add5bff2ede569a1173f08b609c7d9b9cfabdccc91d908ecf5f8e28486620' 
  AND token = 'vFsxWYiVWgGsEgbPJYTvjDZ6d3usZTikAPzvYZTQYVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}